The one thing remaining before I'm happy to
close issue 5.19 is a good treatment in the
guide.
This is what I was looking for as a result of...
> ACTION: Guus, Frank: to move the issue forward, will write up 1-d
> and 2-d views to make clearer to users.
What they wrote 31 Oct is clear enough to the WG...
http://lists.w3.org/Archives/Public/www-webont-wg/2002Oct/0310.html
but I don't think it's text we expect users
to understand.
While the Guide does a great job on many issues,
I disagree with Frank about the treatment
of the species of OWL...
"In general, I think it is fine"
-- Frank van Harmelen, 7 Nov
http://lists.w3.org/Archives/Public/www-webont-wg/2002Nov/0062.html
Text like
The wine ontology as it currently exists
would require the ability to treat classes
as instances
http://www.w3.org/TR/2002/WD-owl-guide-20021104/#Introduction
suggests you can't express classes as instances
in OWL; but you can; You just don't get predicable
reasoning time. The fact that you can do classes
as instances is in the document, but not until
later; and it treats it as some obscure that
"will be of interest to the advanced user,"
while WG discussions have made it clear that
this comes up routinely, and users need
to know about it.
That is, I don't think this text reflects
our discussions:
Another significant difference from OWL DL is that
a DatatypeProperty can be marked as an
InverseFunctionalProperty. These are differences that
will be of interest to the advanced user. This document
does not describe the use of these features.
Er... InverseFunctional Datatype properties are
as common as falling off a log; they're called
database keys in other contexts.
With apologies for not providing specific text
(I haven't found time, but I see this issue
is on our agenda today), I ask that the
guide treat OWL DL and OWL Full as peers,
especially w.r.t. classes as instances.
One approach would be to show the more
straightforward expression of the wine ontology
using classes as instances, then note
the unpredictable nature of reasoning
using those idioms, and then show how
to re-do it within the OWL DL constraints.
--
Dan Connolly, W3C http://www.w3.org/People/Connolly/